4D Flow CMR in Assessment of Valve-Related Ascending Aortic Disease

Abstract

Blood flow imaging with 3-dimensional time-resolved, phase-contrast cardiac magnetic resonance (4-dimensional [4D] Flow) is an innovative and visually appealing method for studying cardiovascular disease that allows quantification of important secondary vascular parameters including wall shear stress. The hypothesis of this pilot study is that 4D Flow will become a powerful tool for characterizing the relationship of aortic valve-related flow dynamics, especially with bicuspid aortic valve (BAV), and progression of ascending aortic (AsAo) dilation. We identified 46 patients previously studied with 4D Flow: tricuspid aortic valve patients without valvular disease (n = 20), and BAV patients with either normal flow (n = 7) or eccentric systolic jets resulting in abnormal right-handed helical AsAo flow (n = 19). The subgroup of patients with BAV and eccentric systolic AsAo blood flow was found to have significantly and asymmetrically elevated wall shear stress. This increased hemodynamic burden may place them at risk for AsAo aneurysm.

False Lumen Status in Patients With Acute Aortic Dissection: A Systematic Review and Meta‐Analysis

“…Furthermore, blood‐flow quantification and velocity mapping can demonstrate bidirectional flow within a false lumen that exhibits partial thrombosis. This turbulent or helical flow can induce aortic wall shear stress, which may be associated with an elevated risk of aneurysmal dilatation or tear 33, 35, 36. Therefore, partial thrombosis of the false lumen in patients with AAD may be reflective of a clinical context in which multiple risk factors exist.…”

Comprehensive Evaluation of Culture-Negative Endocarditis with Use of Cardiac and 4-Dimensional-Flow Magnetic Resonance Imaging

“…Accordingly, 4D-flow MRI might best identify those patients who are in need of urgent intervention. 4 As in our patient's case, difficult clinical presentations often require multiple imaging methods for effective management.…”

“…3 Using the emerging technique of 4D-flow MRI, one can view the entire 3-dimensional volume of the aorta and evaluate the complex forward and regurgitant flow jets, color-coded by velocity, over time. 3,4 High-velocity, eccentric blood flow in an area of asymmetric aortic dilation or aneurysm suggests increased wall shear stress with high potential for rupture. This combination of complete anatomic visualization and evaluation of pathologic hemodynamic conditions is not feasible with echocardiography or conventional CMR.…”

Rationale and methods for quantifying ascending aortic flow eccentricity: Back to the underlying mechanism?

“…The rationale for the need to measure flow eccentricity is that it may play an important pathogenetic role in asymmetric aortic dilatation development (2), likely by increasing local wall shear stress (WSS) at the right-anterior wall (3).…”